A wireless device attempting to establish communication with a wireless communication network typically sends a request for a communication channel to an access node using a random access procedure. A contention based random access procedure is used when, for example, a wireless device is handed over from one access node to another access node, when a wireless device exits an idle mode and attempts to re-establish communication with an access node, when a wireless device temporarily loses communication with an access node and attempts to re-establish communication, when data is available to be transmitted from the wireless device to the access node, etc. In a contention based random access procedure, a wireless device typically sends a channel request over a randomly selected random access channel (RACH). The channel request can comprise a random access preamble. When a channel request is received from the wireless device, the receiving access node can provide a positive indication that access is permitted in a random access response.
However, there exist a limited number of contention-based preambles, and multiple wireless devices transmitting the same preamble may result in a “collision” due to interference between the two identical preambles. As a result, only one of the wireless devices receives a positive indication in the random access response, while the other wireless device needs to re-initiate the contention based random access procedure. This is particularly disadvantageous for devices requiring a higher priority, such as for emergency communications, or real-time applications.